Passengers watch news of Snowden on a train in Hong Kong. Photo: Reuters

Half of Hong Kong people believe that cyberspying whistle-blower Edward Snowden should not be handed over if Washington makes a formal request for his return, according to an exclusive opinion poll commissioned by the Sunday Morning Post.

The poll results, in which only 17.6 per cent of respondents thought Snowden should be sent back, come after hundreds took to the streets yesterday to demand that the 29-year-old former CIA analyst - who is hiding out in the city - not be sent back to the US where he is the subject of a criminal investigation by the Federal Bureau of Investigation.

The findings also came as Chief Executive Leung Chun-ying broke his silence on one of the most diplomatically sensitive episodes in the city's history, saying the case would be handled in accordance with the "laws and established procedures of Hong Kong … when the relevant mechanism is activated".

Leung said the government would "follow up on any incidents related to the privacy or other rights of the institutions or people in Hong Kong being violated". The statement is a clear reference to claims by Snowden in an exclusive interview with the South China Morning Post last week, that the US National Security Agency has hacked into computers in Hong Kong and on the mainland for years.

Snowden also said the US was "trying to bully" Hong Kong over his possible surrender, but last night a government source said: "Under no circumstances can the US bully Hong Kong in any way."

The source rejected as "total nonsense" US media reports that Hong Kong and US government lawyers were working together on the Snowden case.

The Post poll, carried out by the Centre for Communication and Public Opinion Survey at Chinese University found that 49.9 per cent of the 509 respondents were "against" or "strongly against" the government surrendering Snowden to the US if Washington were to ask the city to do so. Only 17.6 per cent said he should be handed over. The rest either refused to answer or had not formed an opinion.

The telephone poll, conducted in Chinese on Thursday and Friday, found that 33 per cent of people regarded Snowden as a hero; 12.8 per cent described him as a traitor; and 36 per cent said he was neither.*

The poll also showed that Hong Kong people across different age groups and education backgrounds held similar views. Male respondents were more likely to see Snowden as a hero, while women preferred not to answer the question.

Civic Party leader Alan Leong Kah-kit said the power to reject any US requests to surrender Snowden was in the hands of the central government.

"According to the agreement to surrender fugitive offenders, the Hong Kong government has no choice but to follow the procedures - unless Beijing chooses to intervene at this stage," he said. "But that, in my opinion, is highly unlikely."

Executive Councillor Regina Ip Lau Suk-yee said it could be "dangerous" for the government to make a decision based on following public opinion at a given point in time.

*Correction: An earlier version said 23 per cent of poll respondents felt Edward Snowden was "something in between" a hero and a traitor. In fact, 36 per cent said he was neither a hero nor a traitor.